If it would help I can post some before and after images that Jeff from PicEngrave edited for me a while back. Seeing the original and the edited one that is run on the laser done by someone who knows what they are doing was a big help for me in learning what a good image to run looks like.
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Halftoner will output DXF or PNG (you click the DXF output tab and just enter a filename with the PNG extension and it figures it out). No SVG, though that wouldnât be hard either.
Most laser software will internally do dithering. In LightBurn whatever you specify as your output DPI is what I resample / dither to if youâre doing dithered output.
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Dithering tends to be easier to deal with - I had good results with dithering in LightBurn very quickly, because as long as you get the dot size and overlap compensation close, the shading is just dark / not dark, and youâre not dealing with curves. Grayscale took considerably longer to dial in.
Iâve written a lot of image resampling and compression code, as well as video compression and playback codecs for video games, so Iâm reasonably familiar with color profiles & spaces, and remapping. So far all my tuning has been âby eyeâ as you say, but it helps to know what your own internal biases tend to be.
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Canât tell from the photo, but is the bottom closed with filter material with a hole for the laser beam?
Either way you could have a safety issue with reflections using that as your only protection.
Here is another tip.
If your focus is correct and you still have an ellipse instead of a circle, you can rotate the laser to align the major axis of the ellipse in either 45 D left or 45 D R and then use that as your engraving mode.
Once done this will have the effect of making the dot size equal when moving vertical or horizontal and when using the 45 D mode you aligned to, will give the thinnest line.
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Not really. Itâs just that the minor axis is the smallest distance of an ellipse.
Think of it like a football. If you look directly into the end of it you see the smallest width. If you rotate the ball then looking at the end of it shows an increase in the width. Only when you look directly down the major axis do you see the thinnest outline.
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Thats what I was trying to say here but didnât explain it well.
Larry did a better job. Let me see if I can elaborate on it in case anyone else reading this thread is having trouble.
When focused correctly the stock lens that comes with the JTech produces an oval shaped beam, not a circle. So if you are engraving on the 45 in PEP and the oval isnt set on the same 45, even though the beam is focused correctly, you wonât get the thinnest line possible. You can loosen the set screw on the heat sink block and turn the entire diode so that the oval is oriented on the same plane.
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Looks like the grain in the wood if you zoom way in. Do you sand your piece before engraving? Sometimes the slightly raised grain on a piece of milled lumber is just a tiny bit harder from the planer knife. A quick rub with some sandpaper before burning can help with that. That would be the first thing I would check.
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Oh ok I see what you mean now. I thought you were talking about the white spots in the greyscale squares.
My bad. Now I see what you are looking at. Do they stay vertical all the time or do they switch to 45 or horizontal when you change the engraving angle?
It must be in how the test pattern is drawn. If it were a resolution issue the lines would always be going the same direction as you are engraving.
I had the little wavy vertical lines when I had a mechanical issue with one of my belts having a frayed spot. I replaced the belt and the lines went away. I would look for a mechanical reason for the artifact.
It is NOT the test pattern.
Maybe not. I assumed based on his comments of only sending tests via pictures from now on that Phil wasnât sending the actual test as an image with the gcode built by PEP. I was speculating that the gcode was created in another program with a dxf or svg and the way it was created was causing the issue. If it was put in PEP and the gcode created in there then you are right and it most likely isnât the test. What are your thoughts @JohnChamplain ?
Rick,
We are working with Phil privately on this issue. I made the test pattern and PEP generated the code. It is a test I have long used, so I know the test image and gcode are not an issue.
The horizontal and vertical lines in the test pattern are solid black and only one pixel wide. Image attached. If downloaded, be sure to save it as a .bmp file so .jpg compression artifacts will not corrupt the pure shades.
John
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@JohnChamplain Thats fine. I was just curious to the issue. I didnât know who made the image or how it was made or how it was sent. I just made a guess based on what we ruled out earlier and the fact that it doesnât happen with the photo of the child. Iâm not knocking the software, the laser, or anyone in any way. Most people know I am one of the most vocal supporters of PEP, PicSender and JTech. I love all three. Just trying to pay forward all the help that was given to me. No reason to get defensive.
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I wanted to but my machine is currently down for upgrades (CNC Demon) 
I hope to get it back up this weekend.
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My apology. Did not mean to sound defensive or insulting in any way. Poor choice of words.
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No problem 
Sorry I took it that way. Its one of those days. Weâre all good.
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Amen. 
Moisture content and distribution would also play a part.
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